Scale Hero Points based on players
The only problem I can see with that is the fact that they are champions. So you can go back daily for loot and xp. If they scale it down it would make is trivial. I usually don’t have too much trouble finding people. Pop a mentor tag and ask in map chat and you can usually find the 2 or 3 people you will need to help you out.
Plus there are guilds, Malum Factum(sp?) is one I know that do what I believe are weekly hero point zergs? There was a post about it on Reddit and in the looking for forum.
The sad thing is that hero points do scale already. Try doing a hero point by yourself and then come back later with a hero point train. Huge amount of adds. So scaling hero points is already a thing, what you’d be more interested in is for the baseline encounters with champs to be dropped to something more soloable.